Some food for thought: There is a saying that "the road to hell is paved with good intentions." So, what this means is that the definition of good versus evil has a blurry line between it. What if someone is 'corrupt' just so that he can pay off the medical bills of his parents? He would do anything it takes to protect his family. How would you brand this person in this economic times?
The fact of the matter is, we all have our own needs and our own way to achieve it. If the thought of saving your family is greater than your own conscience by hurting other people, some people do it. I mean, it's really hard to differentiate or label these people sometimes. But to the outsiders, this person is definitely evil since he is harming others. But not to his family.
My personal opinion is that, man are inherently pure and good. But for some people, it is necessary for them to perform "evil" deeds in order to do good things. If they don't strive to do 'good' things, then they may not need to do these 'evil' deeds after all.' Without light, there is no shadow/darkness. The greater the light, the greater the shadow. Of course, I do not discount that there are people who are just inherently evil. But then again, maybe to me and you. However, we may not think that once you understand their situation. No one wants to be an outcast in my opinion if they have a choice.
Back to the question, if we are having problem defining what is truly good or evil for one man, it would be impossible to define the outcome of being corrupt for every man. Because, corrupt doesn't really mean corrupt for every man. Well, maybe I just believe that people does not choose to be bad/evil. They do it because of the circumstances and to fulfill their needs. Not everyone is born equal. Some is not capable of this reasoning ability and would rather use brute force. To them, with their limited mind power, this is how it should be. Instant gratification. Some does not want to or is capable in thinking for long term needs... There is no way to brand all human.